Hi Michael,

> I had a problem with pcvt on one machine using gcc7.2.2 with -O6.  Once I
> changed it to -O, things work again.
> 
> I don't have time to debug things properly right now, but just in case
> others are having problems as well that is a workaround.

No need for debugging, it's gcc's fault. Try -O6 in combination with 
-fno-strength-reduce. This should work. It's a known problem.

Can we add this option to the makefiles please, or at least to the default
options the gcc uses? Quite a few people will be bitten by this bug.

  Guenther